1. Field of the Invention
The present invention relates to a film transfer sheet and intermediate transfer recording medium capable of forming a protective layer and/or an image on a transfer-receiving member successfully.
2. Description of the Related Art
Conventionally, various thermal transfer methods have been known. In such methods, a thermal transfer sheet comprising a color transfer layer formed on a substrate sheet is heated imagewise from the back face thereof by using a thermal head or the like, to thermally transfer the above color transfer layer to the surface of a thermal transfer image-receiving sheet, thereby forming an image. These thermal transfer methods are loosely classified into two systems depending upon the structure of the color transfer layer, namely, a sublimation transfer type and a heat melting transfer type. The two systems enable the formation of a full-color image. For instance, thermal transfer sheets in three different colors of yellow, magenta and cyan or in four different colors of said three colors and, as needed, black are prepared, and each color image is overlapped on and thermally transferred to the same thermal transfer image-receiving sheet to form a full-color image. With the progresses of various hardware and software applications relating to multimedia, markets for the thermal transfer method have been broadened in the fields of full-color hard copy systems used for computer graphics, static images sent by satellite communications, digital images represented by those of CD ROMs and the like, and analog images of videos and the like.
Specific applications of the thermal transfer image-receiving sheet used in this thermal transfer method are diversified. Typical examples of the application include proof of printing, outputs of images, outputs of layout and design in CAD/CAM, output applications for various medical analysis or measuring instruments, such as CT scans and endscope cameras, substitutions for instant photographs, outputs of photographs of a face and the like in papers of identification, ID cards, credit cards and other cards, combination photographs and commemorative photographs handled in amusement facilities such as amusement parks, game centers, museums and aquariums.
When a melt transfer-type thermal transfer sheet is used to form an image, this method has a weakness that the formed image lacks in durability regarding friction resistance. When a sublimation transfer-type thermal transfer sheet is used to form an image, gradational images such as photographs of a face can be formed precisely. However, this method has a weakness that, unlike an image formed by usual printing ink, the formed image lacks in durability regarding, for example, weatherability, friction resistance and chemical resistance. To solve the problem, a protective layer thermal transfer sheet having a thermal transfer resin layer is overlapped on a thermal transfer image and the thermal transfer resin layer having transparency is transferred using a thermal head, heating roll or the like to form a protective layer on the image. For example, as disclosed in Japanese Patent Application Laid-Open (JP-A) Nos. 2000-80844 and 2000-71626, it is proposed to use a protective layer thermal transfer sheet to transfer and form a protective layer on a thermal transfer image.
Along with the diversification of applications of the thermal transfer image-receiving sheet, there has been an increased demand for forming a thermal transfer image on an optional subject. In general, a special thermal transfer image-receiving sheet having a receptive layer formed on a substrate is used as the subject to form a thermal transfer image thereon. However, there are limitations to the substrate, etc. Accordingly, such a transferring method as disclosed in JP-A No. 62-238791 is proposed, in which using an intermediate transfer recording medium provided peelably with a receptive layer on a substrate and a thermal transfer sheet having a dye layer, a dye is transferred to the receptive layer to form an image and thereafter the intermediate transfer recording medium is heated to transfer the receptive layer to an optional transfer-receiving member.
Even in the method using the above intermediate transfer recording medium, however, a final product having an image formed thereon still has the above-mentioned weakness of lack of durability. On the other hand, JP-A No. 2000-238439 proposed an intermediate transfer recording medium in which a transparent substrate provided with a receptive layer is peelably laminated with a sheet substrate via a resin layer. More specifically, the intermediate transfer recording medium with high durability is proposed wherein, after an image is formed on the receptive layer, the transparent substrate is transferred to a transfer-receiving member together with the receptive layer when the receptive layer surface having the image formed thereon is brought into contact with the transfer-receiving member to transfer the image.